上传数据方法总结

HttpURLConnection为javaAPI提供的一种Rest访问的方式。其支持对Post,Delete,Get,Put等方式的访问。

以下为对于HttpURLConnection对Post等方式访问的一段代码。
=====================================================
package com.sw.study.urlConnection;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import java.util.Map;

public class URLConnectionUtil {
    
    private static final String SERVLET_POST = "POST" ;
    private static final String SERVLET_GET = "GET" ;
    private static final String SERVLET_DELETE = "DELETE" ;
    private static final String SERVLET_PUT = "PUT" ;
   
    private static String prepareParam(Map paramMap){
        StringBuffer sb = new StringBuffer();
        if(paramMap.isEmpty()){
            return "" ;
        }else{
            for(String key: paramMap.keySet()){
                String value = (String)paramMap.get(key);
                if(sb.length()<1){
                    sb.append(key).append("=").append(value);
                }else{
                    sb.append("&").append(key).append("=").append(value);
                }
            }
            return sb.toString();
        }
    }
   
    public static void  doPost(String urlStr,Map paramMap ) throws Exception{
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setRequestMethod(SERVLET_POST);
        String paramStr = prepareParam(paramMap);
        conn.setDoInput(true);
        conn.setDoOutput(true);
        OutputStream os = conn.getOutputStream();    
        os.write(paramStr.toString().getBytes("utf-8"));    
        os.close();          
       
        BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line ;
        String result ="";
        while( (line =br.readLine()) != null ){
            result += "\n"+line;
        }
        System.out.println(result);
        br.close();
       
    }
   
    public static void  doGet(String urlStr,Map paramMap ) throws Exception{
        String paramStr = prepareParam(paramMap);
        if(paramStr == null || paramStr.trim().length()<1){
           
        }else{
            urlStr +="?"+paramStr;
        }
        System.out.println(urlStr);
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setRequestMethod(SERVLET_PUT);
        conn.setRequestProperty("Content-Type","text/html; charset=UTF-8");
       
        conn.connect();
        BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line ;
        String result ="";
        while( (line =br.readLine()) != null ){
            result += "\n"+line;
        }
        System.out.println(result);
        br.close();
    }
   
    public static void doPut(String urlStr,Map paramMap) throws Exception{
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setRequestMethod(SERVLET_PUT);
        String paramStr = prepareParam(paramMap);
        conn.setDoInput(true);
        conn.setDoOutput(true);
        OutputStream os = conn.getOutputStream();    
        os.write(paramStr.toString().getBytes("utf-8"));    
        os.close();          
       
        BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line ;
        String result ="";
        while( (line =br.readLine()) != null ){
            result += "\n"+line;
        }
        System.out.println(result);
        br.close();
               
    }
   
    public static void doDelete(String urlStr,Map paramMap) throws Exception{
        String paramStr = prepareParam(paramMap);
        if(paramStr == null || paramStr.trim().length()<1){
           
        }else{
            urlStr +="?"+paramStr;
        }   
        System.out.println(urlStr);
        URL url = new URL(urlStr);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setDoOutput(true);
        conn.setRequestMethod(SERVLET_DELETE);
        //屏蔽掉的代码是错误的，java.net.ProtocolException: HTTP method DELETE doesn't support output
/*        OutputStream os = conn.getOutputStream();    
        os.write(paramStr.toString().getBytes("utf-8"));    
        os.close();  */
       
        if(conn.getResponseCode() ==200){
            System.out.println("成功");
        }else{
            System.out.println(conn.getResponseCode());
        }
    }
   
    public static void main(String[] args) throws Exception{
        String urlStr = "";
        Map map = new HashMap();
        map.put("username","张三");
        map.put("password","88888");
//        URLConnectionUtil.doGet(urlStr, map);
//        URLConnectionUtil.doPost(urlStr, map);
//        URLConnectionUtil.doPut(urlStr, map);
        URLConnectionUtil.doDelete(urlStr, map);
       
    }
   
   
}

 
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方法中是存在重复的。有些方法是可以通过参数的改变来达到统一，但是那样的做法对于程序的扩展性会有很大的局限性。

还是对于每一种方式提供一个单独的方法进行访问比较好。

在Servlet端，获取参数可以通过

request.getInputStream,及request.getParamter来进行。

其中，当Rest访问传入参数是通过conn的outputStream来进行的，可以通过request.getInputStream来进行参数获取（Post方式可通用）；

当以url?key=value方法传递参数时，可以通过request.getParamter来进行参数获取。（Post方式可通用）

其中request.getInputStream和request.getParamter两种方式不能同时出现。当request.getParamter运行的过程，也是输入流的读取过程。当输入流读取完成后，再次调用时无效的。

附上Servlet端程序
====================
package com.sw.servlet;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class ReceiveDataServlet
 */
public class ReceiveDataServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
      
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ReceiveDataServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("----------get--------------");       
        String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");
        String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");
        System.out.println(username);
        System.out.println(password);
        OutputStream os = response.getOutputStream();
        os.write("get".getBytes("utf-8"));
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("----------post--------------");
        BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream()));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while((line = br.readLine())!=null){
            sb.append(line);
        }       
        System.out.println(sb.toString());
        br.close();
/*        String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");
        String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");
        System.out.println(username);
        System.out.println(password);
*/        OutputStream os = response.getOutputStream();
        os.write("post".getBytes("utf-8"));
    }
   
    @Override
    protected void doDelete(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        System.out.println("----------delete--------------");
        String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");
        String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");
        System.out.println(username);
        System.out.println(password);
        OutputStream os = response.getOutputStream();
        os.write("delete".getBytes("utf-8"));           
    }
   
    @Override
    protected void doPut(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        System.out.println("----------put--------------");
       
    /*    BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream()));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while((line = br.readLine())!=null){
            sb.append(line);
        }       
        System.out.println(sb.toString());
        br.close();*/
       
        String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");
        String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");
        System.out.println(username);
        System.out.println(password);
        OutputStream os = response.getOutputStream();
        os.write("put".getBytes("utf-8"));   
    }

}

 
====================
程序中对于request.getInputStream和getParameter的获取方式可能说明的会多少有些问题，我也是通过几组测试后得出的结论。肯定有我没有测试到得。如果有问题，请指出，我会再看到评论后进行测试，修改。

另外，Apache的HttpClient非常好。封装的详细。在我的工作中也用到过，在以后会对于HttpClient进行有些单独的程序笔记。

这里HttpUrlConnection是同事在别的项目中用到的，用法比较简单，我大体给他简单讲解了一下，简明扼要，功能完备，还是很方便，

所以在这里记下来，留个笔记吧。

btw,最近工作比较忙，有2个月没有写些东西了，在工作中确实还遇到了不少有意思的问题，最近刚好快闲下来了，慢慢整理一下。

新年快乐。
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import java.io.IOException;
import java.util.Enumeration;
import java.util.Properties;

import org.apache.commons.httpclient.Cookie;
import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.PostMethod;

public class Netway {
    private HttpClient httpClient = new HttpClient();

    private String serverURL = "";

    public String postPage(String page) {
        String url = this.getURL(page);
        PostMethod postMethod = new PostMethod(url);
        return this.post(postMethod);
    }

    private String getURL(String page) {
        // TODO Auto-generated method stub
        return "http://" + this.serverURL + "/" + page;
    }

    public String postPage(String page, Properties pdata) {
        String url = this.getURL(page);
        PostMethod postMethod = new PostMethod(url);
        NameValuePair[] data = new NameValuePair[pdata.size()];
        Enumeration keys = pdata.keys();
        int i = 0;
        for (; keys.hasMoreElements();) {
            String k = (String) keys.nextElement();
            String v = (String) pdata.get(k);
            data[i] = new NameValuePair(k, v);
            i++;
        }
        postMethod.setRequestBody(data);
        return this.post(postMethod);
    }

    private String post(PostMethod postMethod) {
        String result = "";
        try {
            int statusCode = httpClient.executeMethod(postMethod);
            // 301 or 302
            if (statusCode == HttpStatus.SC_MOVED_PERMANENTLY
                    || statusCode == HttpStatus.SC_MOVED_TEMPORARILY) {
                Header locationHeader = postMethod
                        .getResponseHeader("location");
                String location = null;
                if (locationHeader != null) {
                    location = locationHeader.getValue();
                    System.out
                            .println("The page was redirected to:" + location);
                } else {
                    System.err.println("Location field value is null.");
                }
            }
            result = postMethod.getResponseBodyAsString();
        } catch (HttpException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        System.out.println(result);
        return result;

    }

    public void setServerURL(String serverURL) {
        this.serverURL = serverURL;

    }

    public String getServerURL() {
        return serverURL;
    }

}

文件:	web.rar
大小:	8KB
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